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Assessing dose to the representative individual
SEPA welcomes the opportunity to comment on the Commission’s draft document on ‘Assessing dose
to the representative individual’ used as supporting material for the draft ICRP 2005 recommendations.
In any further consultation, we would urge the Commission to ensure that all stakeholders are provided
with the means to engage fully. A useful model for relaying technical information to audiences with
various levels of awareness of specific issues is that developed by the organisation ‘GreenFacts’
(http://www.greenfacts.org). GreenFacts provides an information and educational website on
environmental issues in which the information is presented in several layers, beginning with the most
basic description of the issue where terminology is defined, and progressively including more technical
information within each of the subsequent layers. We believe this format provides a valuable approach
for information provision that acknowledges the different needs of stakeholders.
SEPA undertakes assessments to determine dose prospectively and retrospectively, the units for these
assessments are, respectively, the dose constraint and the dose limit. Consistent use of these terms
throughout the document would increase ability of the audience to comprehend the assessment being
discussed. This document is likely to generate confusion over current understanding of the distinction
between statutory limits, and constraints
As a regulator SEPA would welcome guidance from the ICRP on the appropriateness of assessing
uncertainty in dose assessment. Such guidance would ensure comparability for assessments
undertaken by different organisations. A potential contradiction exists between paragraph 47 and 51 on
this matter.
SEPA would agree that the representative individual assessed for radiological protection purposes
should be representative of the most highly exposed individuals in the population. There appears to be
conflict in this approach in paragraph 63 which states that “Established databases suggest that the 95th
percentile of consumption rates for many staple tend to exceed the mean value of the distribution by
approximately a factor of 3. Therefore, with deterministic methods, using the 95th percentile of
behaviour is considered to represent a cautious, but acceptable, assumption for defining a reasonable
and sustainable intake rate”. SEPA would welcome clarity on the intended meaning of this phase and
its relationship to paragraph 53.
It is the view of SEPA that specific habit data can identify unique local activities which have the potential
to become the critical group (such as the consumers of sea mice near Sellafield). Such habits can vary
from site to site as does the potential exposure. Dilution of this variation in using generic national or
regional information can lead to the omission of the critical group from an assessment and may allow
failure to detect the most exposed group – the representative individual.

As a public body committed to openness and transparency, SEPA feels it is appropriate that this
response be placed on the public record. If you require further clarification on any aspect of this
correspondence, please contact Paul Dale, SEPA Corporate Office, at the address shown below.
Yours faithfully
Janice Milne
Head of Environmental Policy